The present disclosure relates to condoms and their use for contraception and prevention of infection. In particular, the present disclosure relates to improved compositions and packaging included with condoms to provide improved condom utility. Most condoms are packaged pre-coated with a lubricant to improve comfort during intercourse. The lubricant may also include agents that provide other beneficial functions, such as desensitizers, spermicides, or microbicides—agents that inactivate or otherwise block infection by sexually transmitted pathogens, including HIV.
The amount of lubricant that has been included with condoms is generally low, particularly on the inner condom surface. As demonstrated in Table 1 below, the inner condom surface of typical commercially available condoms has less than one gram of a lubricant composition.
TABLE 1A. Weight ofB. Weight ofC. Weight of condomintactlubricant on innerand package afterD. Weightpackagecondom surface *washing and drying **of lubricantCondom(grams)(grams)(grams)A-C (grams)TROJAN3.380.232.790.59ENZ ®,lubricatedTROJAN3.830.572.691.14EXTENDEDPLEASURE ®TROJAN3.310.112.900.41ULTRAPLEASURE ®KIMONO2.450.122.010.44MICROTHIN ®LIFESTYLES2.800.142.290.51ULTRASENSITIVE ®with SpermicideDUREX2.990.102.370.62AVANTI ®DUREX3.170.332.480.69PERFORMAX ®MEDTECH4.290.173.710.58INSPIRAL ®* Determined by weighing lubricant wiped off with an absorbent tissue.** Determined by washing condom and package with detergent, rinsing, and drying in a ventilated oven at 40 degrees C.
In addition, typical spermicides and/or microbicides are sufficiently potent to inactivate pathogens and sperm in an entire ejaculate of semen at quantities of less than or equal to several tenths of a gram. Thus, spermicides and/or microbicides function well when present as a small fraction of the volume of a typical ejaculate. However, the spermicidal and microbicidal agents presently used on condoms are non-selective detergents that are highly potent and can be toxic to genital tract epithelium and may paradoxically result in increased susceptibility to infection. Compositions including spermicidal and microbicidal agents are often applied to the inner surface of a condom where the composition can immediately mix with semen after ejaculation and is not wiped off during penile intromission.
Although the small quantities (less than 0.6 grams, as illustrated in Table 1) of lubricant compositions present on the inner surface of commercially available condoms are often adequate due to their high potency, some agents provide benefits at increased quantities. Also, to maintain efficacy of certain agents found in minimally dilutable compositions, increased quantities of the composition must be packaged with condoms. For example, acidic buffering agents are far less toxic to epithelial surfaces but must be present in amounts representing a substantial fraction of the quantity of semen in an ejaculate to be effective.
Known compositions and packaging elements included with condoms present problems associated with providing increased quantities of a composition to the inside of a condom. These problems include insufficient space to load the increased quantity of the composition on the inner surface of the condom. Also, the composition, once loaded, may not be well retained where needed due to the force of gravity or the forces caused by accelerations and decelerations acting on the composition during storage, transport, removal, or application of the condom.
Lubricants are generally applied by the manufacturer to one or both sides of the closed end of the condoms after the condoms are rolled up over the majority of their length, yet the lubricant redistributes over at least the first one to three inches of the condom length because, as illustrated in FIG. 1, the lubricant 12 propagates by capillary action into the spiral space 14 between layers of the rolled portion of the condom 10. Whether or not the lubricant is intentionally applied to both sides, propagation of the composition into this spiral space inevitably results in lubricant contacting both inner surface 16 and outer surface 18 of the condom 10, since this spiral space 14 is bounded by the inner surface 16 on one side and the outer surface 18 on the other side.
Furthermore, the viscosity of these compositions decreases even further during use due to the hypertonicity of the compositions. In particular, high concentrations of low molecular weight compounds, such as polyethylene glycol, glycerol, and propylene glycol, tend to draw water out of the penile skin, thereby diluting the composition and lowering its viscosity to further exacerbate the tendency of the condom to slip from the penis. Providing a large quantity of the type of composition typically provided with condoms may make the condom even more likely to slip due to the composition's low viscosity, and due to the ease with which a large quantity of the composition would spread to cover an excessively large portion of the condom during use.
Another well-known problem is that condoms sometimes break or slip off the penis during use. Although condoms are known to be effective contraceptives and effective at blocking the transmission of sexually transmitted infections including HIV, slippage and breakage of the condoms reduces the effectiveness of their intended barrier function, exposing each sexual partner to the potentially infectious secretions of the other partner. The risk of cervicovaginal exposure to sperm will also increase when condoms break or slip when being used as contraceptives.
Both slippage and breakage of condoms generally result from stresses placed on the condom during use that may cause them to stretch to the point of breakage or to slip partially or completely off the penis. The risk of condom breakage is made greater under circumstances where the inner surface of the condom is poorly adherent to and tends to slip against the penis when viscous drag at the outer surface of the condom causes stress to the condom that might cause it to stretch and break. This problem is exacerbated by low viscosity substances on the inner surface of the condom, such as an internal composition provided with the condom or deposition of semen post-ejaculation.
Condom slippage is also exacerbated by the exposure of the inner surface of the condom to low viscosity substances such as a lubricant provided with the condom and semen. Upon ejaculation, a substantial volume of semen, typically 1 to 6 mL, is deposited within the condom, and is widely distributed throughout the space between the inner surface of the condom and the penis to cover a large fraction of the inner surface of the condom. Due to the low viscosity of liquefied semen, the semen acts as a low viscosity lubricant to increase the tendency of a condom to slip off the penis after ejaculation.
Adherence of a condom to a penis can reduce slippage and breakage and is determined by multiple factors. The factors include size and shape of the condom relative to the penis, and, thus, the degree of compressive force with which the condom grips the penis due to the elastic forces in the condom. Attempts to prevent condom slippage include manufacturing condoms having a high coefficient of friction at its inner surface, condoms with an adhesive band near its open end, and condoms having a constricted region with decreased diameter to grip the penis more tightly at that region. However, condoms are available in a limited number of shapes and sizes. Moreover, if penile detumescence occurs before withdrawal, the reduction in penile size reduces the degree of compressive force with which the condom grips the penis, increasing the chance of the condom slipping off during withdrawal. Therefore, it would be advantageous to provide improved condom adherence to the penis that is independent of the relationship between the size and shape of the condom and that of the penis.
There is therefore a need for improved compositions and methods of preventing condom slippage and delivering increased quantities of a composition containing a beneficial agent.